Re: [css-text] Shaping for break-all/word-break

I'm slow to understand, appreciate your expertise.

On Wed, Mar 9, 2016 at 11:31 AM, Behdad Esfahbod <behdad@behdad.org> wrote:

>
> Not necessarily.  And, that is even if you *can* map.  For example, if you
> have a 'ffi' ligature, there's no way to break in between it without
> shaping.
>

Yeah, let's go with the assumption we can map. That part I can handle.


> But even if it was possible, the results are not necessarily the same.
> That holds true for all scripts and languages, not just Arabic.  It's a
> property of how OpenType works.  Fonts have rules that match arbitrary
> sequences.  For example, a font can have a rule such that if there are five
> "x" glyphs after eachother, then it will replace the middle one with an
> alternate form.  This might not be a realworld example, but that's what
> fonts can do, and there definitely are fonts that do similar things, in
> their 'calt', Contextual Alternates, feature.  When you get to script
> styles like Nastaliq, it happens ALL the time.  But then again, break-all
> and caligraphy is a combination we don't have to fully support.  However, I
> think pretty much any script-style Latin font will also be broken.
>

Let me rephase my question.

When break-all a word of 10 chars at 3:
1. Shape the 3 with the rest as text-after.
2. Shape the 3 without text-after.
3. Shape the 10, find glyphs that map to the 3 chars and use them.

I think you're talking about the diff between 1 and 2, correct? Is 3 still
differ from 1?

If 1 and 3 are the same, it helps our efficiency a bit.

/koji